HERMISSENDA HAS EXCELLENT POTENTIAL FOR USE AS A NON-MAMMALIAN TOXICOLOGICAL MODEL. BY INTEGRATING WHOLE ANIMAL AND CELLULAR/NEURONAL STUDIES ON LEAD TOXICITY WE SHOULD BE ABLE TO STUDY ITS EFFECTS ON THE ADULT ANIMAL~S WELL-DOCUMENTED LEARNING BEHAVIOR AND MEMORY STORAGE. PRELIMINARY FINDINGS INDICATE THAT LEAD AT LOW CONCENTRATIONS DELAYS EMBRYONIC DEVELOPMENT OF HERMISSENDA AND IS EMBRYOTOXIC AT HIGHER CONCENTRATIONS. NEURONS IN CELL CULTURE ALSO SHOW GROSS MORPHOLOGICAL CHANGES. STUDIES WITH THE CALCIUM-SELECTIVE VIBRATING PROBE DEMONSTRATE A PERTURBATION DURING LEAD APPLICATION ON APLYSIID NEURONS. UNEXPECTEDLY THE EFFLUX INCREASES. THE MECHANISM BEHIND THIS IS UNKNOWN AND THE SUBJECT OF FURTHER INVESTIGATION IN CONJUNCTION WITH STUDYING THE BIOLOGICAL ACTION OF LEAD THIS SYSTEM WILL BE USED TO DEVELOP A LEAD-SELECTIVE VIBRATING PROBE. WITH SUCH A NEW CAPABILITY WE WILL BE ABLE TO FOLLOW CELLULAR LEAD LOADING AND UNLOADING DIRECTLY. DR. H. EPSTEIN, EMERITUS PROFESSOR, BRANDEIS UNIVERSITY, MA ALSO PARTICIPATED IN THIS STUDY.